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AIX Tips & tricks

Below are few of the AIX commands which will be useful for AIX admins.

The output will look like:
compression: off
path specification: on
corefile location: /corefiles
naming specification: off

6. To make any process run by root dump compressed core files and restore the location of the core files to the system default,

# chcore -c on -p default root
Note: If no default is specified, cores will dump in the current directory.

7. To enable a default core path for the system, type:

# chcore -p on -l /corefiles -d

8.
To scan logical volume lv01, report the status of each partition, and
have every block of each partition read to determine whether it is
capableof performing I/O operations, type:

# mirscan -l lv01

9. To do the above operation in a PV,

# mirscan -p hdisk1

10. To do the above operation in a VG,

# mirscan -v vg01

11. To determine if the 64-bit kernel extension is loaded,

# genkex grep 64

12. To list all JFS file systems,

# lsjfs

13. To list all JFS2 file systems

# lsjfs2

14. To mirror a terminal1 on terminal2
a. Open terminal 1 and find the pts value (ps -ef grep pts)

b. Open terminal 2 and enter 'portmir -t pts/1'
c. Now you will see commands and outputs from terminal 1 in terminal 2.
This is basically monitor a terminal.
d. Say "portmir -o" to end the mirroring after the use

15. To identify the current run level,

# cat /etc/.init.state

16. To list the available CD ROM drives,

# lsdev -Cc cdrom

17. To find out the speed of your network adapter,

# entstat -d ent0 grep "Media Speed"

18. To find out when your system was last installed/updated

# lslpp -f bos.rte

19. To list the status of your tape drive,

# tctl -f /dev/rmt0 status

20. How to setup anonymous ftp in AIX

Run the below script to setup anon ftp,
# /usr/lpp/tcpip/samples/anon.ftp

21. If telnet takes more time to produce a prompt, do the below checks

a. do nslookup of the client ip from the aix serverb.
b. Check the nameservers in /etc/resolv.confc.
c. Check the 'hosts' entry in /etc/netsvc.conf or NSORDER variable

This issue might be due to the DNS configuration issue. Pointing to a good nameserver should solve the problem.

22. How to shutdown the system to maintenance mode ?

# shutdown -Fm

23. How to log ftp accesses to a file

a. Add the below line in /etc/syslog.confdaemon.debug /tmp/daemon.log
b. # touch /tmp/daemon.log
c. # refresh syslogd
d. Modify your inetd.conf so that ftpd is called with the "-l" flag.

24. How to find a file name from inode number ?

# ncheck -i xxxx /mountpoint
where xxxx -> inode number of the file

25. How to redirect the system console to a file or tty temporarily

# swcons /tmp/console.out

or

# swcons /dev/tty5

26. How to recreate a deleted /dev/null file ?

# /bin/mknod /dev/null c 2 2

27. How to add commands that should get executed during every system shutdown ?

Add them to /etc/rc.shutdown

28. How to reduce the size or do cleanup of /var/adm/wtmp ?

# > /var/adm/wtmp

29. How to find out the fileset a file belongs to ?

# which_fileset command_name

30. In which file, the mapping of file Vs fileset stored ?

# /usr/lpp/bos/AIX_file_list

31. How to set maximum logins for a user in a system ?

Change the value of "maxlogins" under "usw" stanza in /etc/security/login.cfg

32. How to change the initial message that prints while logging in ?

Change the value of "herald" in /etc/security/login.cfg

33. How to set the # of seconds the user is given to enter their password ?

Change the value of "logintimeout" under "usw" stanza in /etc/security/login.cfg